1. Field of the Invention
This invention relates to an ironing shoe with a fastening device for fastening and releasing the fastener of a pressing surface of an electric steam iron, with a soleplate base having soleplate openings for the discharge of steam, the underside of which is used for ironing the article needing to be ironed and the upper side of which has disposed thereon an insert arrangement having insert openings for the passage of steam from the steam iron to the soleplate openings. The present invention relates in addition to an electric steam iron with a detachable ironing shoe.
2. Description of the Related Art
An ironing shoe of this type is known in the art from DE 2 612 848. In this disclosure the soleplate base is equipped with a perforation into which an insert made of tetrafluoroethylene or silicate rubber is inserted. The insert has a large insert opening so that no diminishing of the steam pressure results from the insert itself but a certain diminishing of the steam pressure can arise due to the fine perforation in the soleplate base. Droplets of condensate can form disadvantageously and be discharged as droplets through the soleplate base onto the article to be ironed. Furthermore, fastening the ironing shoe to a steam iron is a relatively elaborate operation.
It is an object of the present invention to provide an ironing shoe and an electric steam iron having a detachable ironing shoe of the type initially referred to, which features optimal utility characteristics.
This object is accomplished by an ironing shoe incorporating the features of claim 1 and by an electric steam iron incorporating the features of claim 11.
Advantageously, the insert arrangement comprises a capillary layer made of a moisture-absorbing material inserted in the soleplate base so that it is arranged on the upper side of the soleplate base, meaning the side facing away from a pressing surface on the soleplate base. In addition, the insert arrangement comprises an impermeable layer or insert element arranged on the side close to the steam iron. The capillary layer of this multi-layer insert arrangement prevents droplets of condensate from the conveyed hot steam, caused by the less heat-conductive material, from escaping through the soleplate base. Instead, any droplets of condensate which may form are absorbed by the capillary layer, ultimately evaporating again on the hotter parts of the soleplate base. The impermeable layer, which is arranged on top of the capillary layer and lies in direct contact with the ironing side of the electric steam iron, has several functions. Imperviousness to liquids and steam prevents any lime contained in the steam from depositing between the pressing surface of an electric steam iron and the insert. If used without the impermeable layer the pressing surface, following use with the ironing shoe, would be covered with lime particles which would then be applied directly to the article being ironed. Furthermore, the impermeable layer contributes to ensuring that the steam flows from top to bottom and not vice versa, meaning that the layer also acts as a seal relative to the pressing surface of the iron. The impermeable layer has not only impermeable characteristics but is also resistant to high temperatures, enabling it to be exposed to a maximum iron temperature of 240xc2x0 C. without the insert material suffering any impairment. Hence the capillary layer can be made of relatively low-cost material without the need of any heat-resistant coating or capillary layer. Furthermore, the impermeable layer affords ease of cleaning on account of its imperviousness to liquids and displays high abrasion and wear resistance so that the capillary layer does not become worn by regular fastening and releasing of the shoe fastener on the pressing surface of an electric steam iron. Finally, the impermeable layer prevents the pressing surface of the iron from sticking to the shoe.
The insert arrangement is preferably constructed so that an average temperature of 175xc2x0 C. to 210xc2x0 C. applied to the impermeable layer is reduced to an average temperature of 90xc2x0 C. to 120xc2x0 C. on the underside of the soleplate base. The insert is constructed so that this reduction of temperature of the pressing surface of an electric steam iron equals an adjustment from a 3-point setting to a 1-point setting corresponding to an average temperature of the shoe""s pressing surface. Hence the ironing shoe insulates or reduces an applied temperature by at least around 40 or 55 Kelvin. A higher temperature insulating effect by the shoe of up to 120 or 150 Kelvin and more is also achievable. The shoe is intended in particular for an electric steam iron having a drip valve and a steam generating chamber so that water drips from the water tank into the steam generating chamber in the steam iron itself, independently of external steam generators, enabling steam to be produced there as a function of the temperature setting, starting at a temperature corresponding to the 2-point setting (=125xc2x0 C. to 160xc2x0 C.). Nearly the maximal amount of steam is produced in the 3-point temperature setting of the electric steam iron. On the other hand it is desirable for more sensitive types of fabric, which should be ironed only in the 1-point setting (average temperature of 90xc2x0 C. to 120xc2x0 C. at the pressing surface), to be also steam ironed with the shoe so that any type of article (including synthetic items) can very easily be ironed, crease-free, with the aid of hot steam and the shoe. The formation of shiny areas by the shoe is also prevented.
In a further advantageous embodiment the soleplate base is made of aluminum, particularly of aluminum surface-hardened by anodizing. In addition to the known outstanding forming properties of aluminum, which are important particularly for pressing surfaces with their numerous beads and indentations and cutouts, aluminum displays very high thermal conductivity. In addition to this there is also a special advantage to using aluminum as the material for the soleplate base of an ironing shoe because it exhibits high thermal emissivity and so contributes to maintaining the desired low temperatures at a constant level throughout the periods of different iron uses so that, for example, after putting down the iron in vertical position it does not overheat the item being ironed if used immediately afterwards. Advantageously, at least the pressing surface of the soleplate base is surface-hardened by anodizing or hard-anodizing.
In a still further advantageous embodiment the capillary layer is made of a fabric material, particularly polyester mat. Other moisture-absorbing fabric materials such as PPS, PE or cotton, other mat materials or fabrics can also be used for the capillary layer. High-temperature-resistant materials such as Nomex and Kevlar or the like are less preferred for cost reasons and are not necessary with the structure selected here because the impermeable layer already protects the underlying capillary layer from excessive contact heat on account of its high heat resistance.
In a further advantageous embodiment the ironing shoe is provided with a seal to prevent steam escaping from the outer upper edge. The purpose of the seal is to prevent hot steam escaping from the gap between the circumferential edge of the shoe and the circumferential edge of the steam iron in addition to the venting of steam through the soleplate openings. The seal prevents steam from escaping from underneath the insert between the insert and the soleplate base as well as from above the insert between the insert and the pressing surface of the electric steam iron outwards in the direction of the upper edge. This is accomplished, for example, by applying increased pressure in urging the insert in the outer edge zones against the pressing surface of the iron. For this purpose provision is made either for a circumferential silicone adhesive seal, which changes the height of the insert at the edge, or preferably for a second capillary layer which is of an annular configuration shaped to conform to the outer contour of the soleplate base so that the insert is pressed more in this outer zone by the steam iron against the soleplate base.
In an advantageous further aspect the impermeable layer is made of an aluminum material. The aluminum material has all the properties required of this layer: It is impermeable to liquid and steam, is resistant to high temperatures, can very easily be punched and formed, and has adequate wear resistance. Alternatively, it is possible to use Kapton, other rust-proof materials, PTFE, PPS, silicone and glass fiber materials.
In advantageous manner, the insert openings are formed as cutouts in the impermeable layer and in the capillary layer in the front area of the nose portion and in laterally adjoining areas near the lateral contours of the soleplate base. The shoe is intended for a steam iron having steam discharge ports arranged in a U or V pattern with the point of the V at the end close to the iron""s nose portion. The steam discharge ports/soleplate openings in the soleplate base are arranged essentially for registration with the steam discharge ports in the pressing surface of the steam iron. An essential difference is that in the steam iron the discharge ports are arranged in slot-like or tear-shaped bead recesses in which there are individual circular openings for the steam to exit, whereas the steam discharge ports in the ironing shoe are not provided with individual circular openings but as elongated openings. To enable an unimpeded flow of steam between these two steam discharge ports, the insert in these areas has cutouts provided in both the impermeable layer and the capillary layer.
The soleplate base is preferably constructed in the form of a trough whose edge in the area of the nose portion is bent inwardly at an acute angle and at the opposite end is bent upwardly at essentially right angles so that a steam iron can be placed first under the edge of the nose portion for attachment and then lowered onto the opposite rear area of the soleplate base. Unlike the ironing shoes known from the art, which in the area of the nose portion have no bevel and are therefore less suited for ironing shirt pockets and shirt sleeves, this option remains possible when attaching the shoe to the steam iron. Furthermore, the inward bevel of the soleplate base serves the added function of securing the shoe to the steam iron in a simple positive-engagement relationship thereto in one end area without needing any further fastening means because this particular nose area of the edge of the soleplate base, which is inwardly bent at an acute angle, embraces the nose area of the edge of the steam iron, which is inwardly bent at an acute angle, in a positive-engagement relationship thereto. Accordingly, the steam iron is guided first under this edge zone of the soleplate base in the area of the nose portion and then simply lowered onto the shoe""s rear area.
The fastening device is advantageously equipped with a spring-loaded snap fastener which snap-locks into place automatically for fastening to the steam iron. This snap fastener is positioned in the shoe""s rear area, that is, in the area remote from the nose portion. It is thus possible to fasten the steam iron to the shoe without using your hands. This is important inasmuch as at least the steam iron is usually hot.
In an advantageous further aspect the fastening device is fabricated from a poor heat-conducting material, particularly a plastic material, with which the user disconnects the shoe from the steam iron when required. It is thus possible for the user to simply place one hand on the handle of the steam iron and the other hand on the plastic fastening device and to pull back the fastening device against the bias of the spring, holding only the steam iron tightly and guiding it upwards, in order very simply to disconnect the steam iron from the shoe.
Advantageously, the present invention also relates to an electric steam iron having a detachable shoe in accordance with at least one of the above mentioned features.
Further objects, advantages, features and application possibilities of the present invention will become apparent from the subsequent description of an embodiment in conjunction with the accompanying drawing. It will be understood that any single feature and any meaningful combination of single features described and/or represented by illustration form the subject-matter of the present invention, irrespective of their summary in the patent claims or their back references.